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MD4(3)		       FreeBSD Library Functions Manual			MD4(3)

     MD4Init, MD4Update, MD4Pad, MD4Final, MD4End, MD4File, MD4FileChunk,
     MD4Data --	calculate the RSA Data Security, Inc., ``MD4'' message digest

     Message Digest (MD4, MD5, etc.) Support Library (libmd, -lmd)

     #include <sys/types.h>
     #include <md4.h>

     MD4Init(MD4_CTX *context);

     MD4Update(MD4_CTX *context, const void *data, unsigned int	len);

     MD4Pad(MD4_CTX *context);

     MD4Final(unsigned char digest[16],	MD4_CTX	*context);

     char *
     MD4End(MD4_CTX *context, char *buf);

     char *
     MD4File(const char	*filename, char	*buf);

     char *
     MD4FileChunk(const	char *filename,	char *buf, off_t offset,
	 off_t length);

     char *
     MD4Data(const void	*data, unsigned	int len, char *buf);

     The MD4 functions calculate a 128-bit cryptographic checksum (digest) for
     any number	of input bytes.	 A cryptographic checksum is a one-way hash-
     function, that is,	you cannot find	(except	by exhaustive search) the in-
     put corresponding to a particular output.	This net result	is a
     "fingerprint" of the input-data, which does not disclose the actual in-

     MD4 is the	fastest	and MD5	is somewhat slower.  MD4 has now been broken;
     it	should only be used where necessary for	backward compatibility.	 MD5
     has not yet (1999-02-11) been broken, but sufficient attacks have been
     made that its security is in some doubt.  The attacks on both MD4 and MD5
     are both in the nature of finding "collisions" - that is, multiple	inputs
     which hash	to the same value; it is still unlikely	for an attacker	to be
     able to determine the exact original input	given a	hash value.

     The MD4Init(), MD4Update(), and MD4Final()	functions are the core func-
     tions.  Allocate an MD4_CTX, initialize it	with MD4Init(),	run over the
     data with MD4Update(), and	finally	extract	the result using MD4Final(),
     which will	also erase the MD4_CTX.

     The MD4Pad() function can be used to pad message data in same way as done
     by	MD4Final() without terminating calculation.

     The MD4End() function is a	wrapper	for MD4Final() which converts the re-
     turn value	to a 33-character (including the terminating '\0') ASCII
     string which represents the 128 bits in hexadecimal.

     The MD4File() function calculates the digest of a file, and uses MD4End()
     to	return the result.  If the file	cannot be opened, a null pointer is
     returned.	The MD4FileChunk() function is similar to MD4File(), but it
     only calculates the digest	over a byte-range of the file specified,
     starting at offset	and spanning length bytes.  If the length parameter is
     specified as 0, or	more than the length of	the remaining part of the
     file, MD4FileChunk() calculates the digest	from offset to the end of
     file.  The	MD4Data() function calculates the digest of a chunk of data in
     memory, and uses MD4End() to return the result.

     When using	MD4End(), MD4File(), or	MD4Data(), the buf argument can	be a
     null pointer, in which case the returned string is	allocated with
     malloc(3) and subsequently	must be	explicitly deallocated using free(3)
     after use.	 If the	buf argument is	non-null it must point to at least 33
     characters	of buffer space.

     The MD4End() function called with a null buf argument may fail and	return
     NULL if:

     [ENOMEM]		Insufficient storage space is available.

     The MD4File() and MD4FileChunk() may return NULL when underlying open(2),
     fstat(2), lseek(2), or MD4End(2) fail.

     md4(3), md5(3), ripemd(3),	sha(3),	sha256(3), sha512(3), skein(3)

     R.	Rivest,	The MD4	Message-Digest Algorithm, RFC 1186.

     R.	Rivest,	The MD5	Message-Digest Algorithm, RFC 1321.

     H.	Dobbertin, "Alf	Swindles Ann", CryptoBytes, 1(3):5, 1995.

     MJ. B. Robshaw, "On Recent	Results	for MD2, MD4 and MD5", RSA
     Laboratories Bulletin, 4, November	12, 1996.

     These functions appeared in FreeBSD 2.0.

     The original MD4 routines were developed by RSA Data Security, Inc., and
     published in the above references.	 This code is derived directly from
     these implementations by Poul-Henning Kamp	<>.

     Phk ristede runen.

     The MD5 algorithm has been	proven to be vulnerable	to practical collision
     attacks and should	not be relied upon to produce unique outputs, nor
     should they be used as part of a cryptographic signature scheme. Copy-
     right (C) 1991-2, RSA Data	Security, Inc. Created 1991. All rights	re-

     License to	copy and use this software is granted provided that it is
     identified	as the "RSA Data Security, Inc.	MD4 Message-Digest Algorithm"
     in	all material mentioning	or referencing this software or	this function.
     License is	also granted to	make and use derivative	works provided that
     such works	are identified as "derived from	the RSA	Data Security, Inc.
     MD4 Message-Digest	Algorithm" in all material mentioning or referencing
     the derived work.

     RSA Data Security,	Inc. makes no representations concerning either	the
     merchantability of	this software or the suitability of this software for
     any particular purpose. It	is provided "as	is" without express or implied
     warranty of any kind.

     These notices must	be retained in any copies of any part of this documen-
     tation and/or software.

FreeBSD	13.0			 May 21, 2019			  FreeBSD 13.0


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